Cyanines from triazolo bases



' thiazole,

United States Patent CYANINES FROM TRIAZOLO BASES Leslie G. S. Brooker and Earl J. Van Lare, Rochester, N. Y., assignors to Eastman Kodak Company, Roch ester, N. Y., a corporation of New Jersey No Drawing. Application January 9, 1957 Serial No, 633,184

11 Claims. (Cl. 96-106) wherein R and R each represents an alkyl group, such as methyl, ethyL-propyl, isopropyl, butyl, isobutyl, allyl (vinylmethyl), fl-hydroxyethyl, benzyl (phenylmethyl),

etc. (e. g., an alkyl group of the formula C H wherein m represents a positive integer of from 1 to 4), n represents ra positive integer from 1 to 2, X represents an acid radical, such as chloride, bromide, iodide, perchlorate, benzenesulfonate, p-toluenesulfonate, methylsulfate, ethylsulfateyeto, Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzothiazole series or the quinoline series, and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing from to 6 atoms in the heterocyclic ring, such as those selected from the group consisting of those of the thiazole series (e. g., thiazole, 4-inethylthiazole, i-phenylthiazt le, 5 methylthiazole, .i-phenylthiazole, 4,S-dimethylth'iazole, 4,5-diphenylthiazole, 4 (2-thienyl) thiazole, etc.), those of the benzothiazole series (e. g., benzothiazole, 4-chlorobenzothiazole, 5-chlorobenzothiazole, 6- chlorobenzothiazole, 7-chloroben zothiazole, 4-methy1benzothiazole, 5'-rnethylbenzothiazole, 6-methylbenzothiazole, S-bromobenzothiazole, 6-bromobenzothiazole, S-phenylbengothiazole, 4-methoxybenzothiazole, .S-methoxybenzothiazole, 6-methoxybenzothiazole, JS-iOdQbeniO: 6-iodobenzothiazole, 4-ethoiiybenzothia zole, S-ethoxybenzothiazole, tetrahydrobenzothiazole, 5,6-di methoxybenzothiazole, 5,6-dioxymethylenebenz'othiazole, 5 -hydroxybenzothiazole, 6-hydroxybenzothiazole, etc.)

those of the naphthothiazole series (e. g., a-naphthothia- 5-methoxy-p-naphthothiazole,

zole, ,B-naphthothiazole, 5-ethoxy-B-naphthothiazole, S-methoxy-a-naphthothiazole, 7-methoxy-a-naphthothiazole, etc.), those of the thianaphtheno-7',6',4,5-thiazole series (e. g., 4'-methoxythianaphtheno-7',6,4,5-thiazole, etc.), those of the oxazole series (e. g., 4-methyloxazole, S-methyloxazole, 4-phenyloxazole, 4,5 diphenyloxazole, 4-ethyloxazole,-4,5-dimethyloxazole, 5-phenyloxazole, etc.), those of .the benzoxazole series (e. g., benzox'azole, S-chlorobenzoXazole, S-methylbenzoxazole, S-phenylbenzoxazole, G-methylbehzoxazole, 5,6-dimethylbenaoxazole, 4,6-dimethylbenzoxazole, 5-

2,870,014 Patented Jan, 20, 1959 methoxybenzoxazole, S-ethoxybenzoxazole, 5v-chlorobenzoxazole, 6-methoxybenzoxazole, S-hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.), those of the naphthoxazole series (e. g., OCrI'IaPhthOXHZOIC, S-naphthoxazole, etc.), thoseof the selenazole series (e. g., 4: methy1selenazole,

4-.Phenylselenazole, etc.), those of the benzoselenazole series (e. g., benzoselenazole, S-chlorobenzoselenazole, 5 methoxybenzoselenazole, 5 hydroxybenzoselenazole, tetrahydrobenzoselenazole, etc.), those of the naphthoselenazole series (e. g., a-naphthoselenazole, B-naphthoselenazole, etc.), thoseof the thiazoline series (e. g., thiazoline, 4methylthiazoline, etc.), those of the 2-quinoline series (e. g., quinoline, 3-rnethylquinoline, S-methylquinoline, 7-methylquinoline, S-methylquinoline, 6-chloroquinoline, 8-ch1oroquinoline, o methoxyquinoline, -,6-ethoXyquinoline, 6-hydroxyquinoline,- 8-hydroxyquinoline, etc. those of the 4-quinoline series (e. g., quinoline, 6-meth- I series (6. g., pyridine, S-methylpyridihe, etc.), etc.

oxycpdinoline, 7-methylquinoline, 8-Inethylquino1ine, etc.)

those of the l-isoquinoline series (e. g., isoquinolin'e, 3,4-dihydroisoquinoline, etc.) those of the 3-isoquinol1ne series (e. g., isoquinoline, etc.), those of the benzimidazolel series (or g., 1,3-diethy1benzimidazole, 1-ethyl-3-phenylbenzimidazole, etc.), those of the 3,3-dialkylindolenine series (e. g., 3,3-dimethylindolenine, 3,3,5-trimethylindolenine, 3,,3,7 trimethylindolenine, etc.), the pyridine It is, therefore, an object of our invention to provide new cyanine dyes. A further object'is to provide methods for making these dyes. Still another object is to provide new cyanine dye intermediates.- -Another object is to provide methods for making these new intermediates. A further oogect is to provide photographic silver halide emulsions sensitized with the new dyes of our invention.

' Qther objects will become apparent from a consideratio of the following description and examples.

According to our invention, We provide the dyes represented by Formula I above by condensing a compound selected from those represented by the following general formula: 7

wherein R, X and Z each have the values given above,

together with a compound selected from those representedbythe following general formula-z III. i

4-phenylbenzoth-iazole,

etcga'nd R represents an aryl' group; such as phenyl,

0-, m-, and p-t'olyl, etc. (*e. g;, a monocyclic aromatic group of the benzene series).

the condensations can -advantageously be carried out injthe presence of a basic condensing agent, such;as the trialkylamines (e, g., triethylamine, tripropylamine, vtriisoprcpylarnine, tributylarnine, triisobutylamine, triamyk amine, etc.), the N,N-dialkylan ilin es (e. g. N,N- dim ethy le I aniline, N,N-diethylaniline, etc.), the N-alkylpiperidines (e. g,N-methylpiperidine, N-ethylpiperidine,-ietc.)', etc.-

C-CHs wherein Z has the values given above, with an alkyl salt representedby the following general formula:

whereinR and X- each have the values given above. Temperatures varying from about the temperature of the steam bath to about 200 C. can be employed.

Thev intermediates represented by Formula IV above can be prepared by condensing a compound selected from those represented by the following general formula:

wherein Z has the values given above, together with acetic anhydride in the presence of a strong acid, e. g., glacial acetic acid, phosphoric acid, etc. Where the condensation is slow, improved results can be obtained by first acetylating the hydrazine group of the compound of Formula VI, purifying the acetylated intermediate by crystallization, and completing the condensation by adding fresh acetic anhydride and strong acid, and heating under reflux. See also our copending application Serial No. 593,615, filed June 25, 1956. The carbocyclic ring of the compounds represented by Formula VI can contain simple substituents, such as chlorine, bromide, iodine, methoxyl, ethoxyl, methyl, ethyl, phenyl, etc. Intermediates represented by Formula .VI above have been previously described in Brooker U. S. Patent 2,743,274, issued April 24, 1956, and Bayer et a1. U. 3. Patent 2,073,600, issued March 16, 1937.

The following examples will serve to illustrate more fully the manner whereby we practice our invention.

Example 1.1-methyl-s-triaz0lg[4,3-a]quin0line 2-quinolylhydrazine (31.8 g., 1 mol.), acetic anhydride (40.8 g., 2 mols.) and glacialtacetic acid (100 ml.) were refluxed together for 1 hour. The reaction mixture was poured into 1 liter of water, neutralized with sodium carbonate, and then made strongly alkaline with sodium hydroxide. The mixture was extracted several times with ether to remove the unchanged quinolylhydrazine. On standing, a heavy oil, insoluble in water, ether, benzene and chloroform,'slowly separated from the aqueous solution. =After standing for two weeks the oil became crystalline. It was filtered off and recrystallized from ethyl acetate. A 65% crude yield of colorless crystals was obtained, M. P. 155-158" C.

Example 2.-2-ethyl-I methyl-s-triaz0lo[4,3-a] quinolinium iodide 1methyl-s-triazolo[4,3-a]quinoline (9 g., 1 mol.) and ethyl iodide (12 g., 1% mols.) were heated on a steam bath for 4 hours. The solid was ground in a mortar with acetone, filtered off and washed well with acetone. A 74% yield of tan crystals was obtained, M. P. 192-194 C. dec.

Example 3. 1-methyl-s-triazolo[3,4-b]benzothiazole Z-acetylhydrazinobenzothiazole (10.4 g., 1 mol.), acetic anhydride (50 ml.) and phosphoric acid (0.5 ml.) were refluxed together for 1 hour. The reaction mixture was poured into 400 ml. of water with stirring. The mixture was made alkaline with sodium carbonate solution, and the product filtered off and washed with water. After recrystallization from methyl alcohol an 81% yield of colorless crystals was obtained, M. P. l42-144 C.

Example 4.--2-ace tylhydrazinoberzzozhiazoie C-NH-NHC OCH:

Z-hydrazinobenz'othiazole (33 g., 1 mol.), acetic anhydride (40.8 g., 2 mols.) and acetic acid ml.) were refluxed together for 1 hour. The acetic'acid and acetic anhydride, were removed on a steam bath under reduced pressure. The residue was dissolved in ethyl alcohol (200 ml.) and the solution made alkaline with 10% potassium carbonate solution. The mixture was cooled and the solid filtered off, washed with water and then with ethyl alcohol. After recrystallization from methyl alcohol, a 53?: yield of colorless crystals was obtained, M. P. 213 21 C.

Analysis.Calcd for C H N OS: C, 52.1; H, 4.3.. Found: C, 52.3; H, 4.3.

Example 5.2',3-diethyl0xa-I -s-triazol0[4,3-a]- quinocarbocyanine iodide.

A 610 mu with a maximum at 85 mu.

Z-ethykl-methyl s-triazolo[4,3 alquinolinium iodide (1.7 g., 1 mol.), 2-,8-acetanilidovinylhenzoxazole ethiodide (2 .2 g., 1 mol.), pyridine (10 m1.) 'andtriethylamine (0.5 g., 1 mol.) were refluxed together for 1 hour. The reaction mixture was cooled and the dye precipitated with ether as a heavy oil. The oil was washed with ether and thenstirred with a small amount of ethyl alcohol. After cooling for 1 hour the solid, which separated, was filtered off and washed with ethyl alcohol. After two recrystallizations from methyl alcohol, a 14% yield of orange needles was obtained, M.l?. 256-257 C. dec. The dye sensitized a gelatino-silver-'oromiodide emulsion to 545 mu with a maximum at 515 mu. 1 i Y Y Example 6.3-ethyl-2-methyloxa-1-s-triozolo[3,4-b1- benzothiazolocarbocyanine iodide l-methyl-s-triazolo[3,4-b]benzothiazole (1.9 g., 1 mol.) 3

After chilling, the solid was filtered oif, washed lightly with methyl alcohol and then with acetone. The crude dye was dissolved in methyl alcohol and filtered hot through a bed. of Nor-it. After chilling, the solid was filtered off and Washed lightly with methyl alcohol. (After recrystallization from methyl alcohol, a, 15% yi'eld of scarlet crystals was obtained, M. P. 259-260 C. dec. The dye sensitized a gelatino-siiver-bromiodide emulsion to 565 mu with a maximum at 550 Analysis.Calcd for C H IN QS; I, 25.3. Found: I, 25.7.

Example 7.-3-ethyl-2 '-methylthia-1 -s-tr iazolo [3,4 -b l benzothiazolucarbocyanine iodide.

1-methyl-s-triazolo[3,4-blbenzothiazole' (1.9 g., 1 mol.) and methyl p-toluenesulfonate (1.9 g., 1 mol.) were heated together at 160-170 C. for 3 hours. After cooling,. 2-}8-acetanilidovinylbenzothiazole ethiodide (4.5 g., 1 mol.), pyridine (10 ml.) and triethylamine (2 g.,

2 mole.) were added and the mixture'was refluxed for '5 trous darkredneedles was obtained, M. P 270 271" It sensitized a gelatino-silver-bromide emulsion: to

dec.

ben zothiazolocarbocyanine iodide l-methyl-s-triazolo[3,4-b]benzothiazole (1.9 g., 1 mol. plus 100 percent excess) and methyl p-toluenesulfonate (1.9 g., 1 mol. plus 100 percent excess) were heated together at 160-170" C. for 3 hours, After cooling, 2-[3- tered off and washed with 'Water and thenwith acetone.

After two recrystallizations from methyl alcohol, a 12 percent yield of reddish needles with a green'r'eflux was obtained, M. P. 262-263 C. dec. It sensitized a gelatinos silver-bromio'clide emulsion to '590 mu' with a maximum at 550 mu. Example 9.3-ethyl-2'-methyl-4,5-benzothiq-1' s-tria z0lo[3,4-b]-benz0thiazolocarbocyanine iodide l-methyl-s-triazolol3,4rb]benzothiazole (1.9 g., 1 mol. plus 100 percent excess) and methyl p-toluenesulfonate 1.9 g., 1 mol. plus 100 percent excess) were heated together at 160-170 C.-for 3 hours. After cooling, 2- B-anilinovinylnaphtho 1,2] thiazole etho-p-toluenesulfonate (2.5. g., 1 mol.), pyridine (10 ml.), triethylamine (1.35 g., Zmols. plus 35 percentexcess), and acetic anhydride (0.5 g., 1 mol.) were added and the mixture was refluxed for 10 minutes. After chilling, the solid was filtered off, washed with water and then with acetone. After two recrystallizations from ethyl alcohol, a 38 percentvyield of reddish crystals were obtained M. P. 23 8-239 C. dec. The dye sensitized a gelatino-silverbromiodide emulsion to 600 mu with a maximum at 570 Example 1 0 -3-ethyl- V '-methyloxa-1 -s-t riaz0 lo- [4,3-a1-quinocarbocyanine iodide (l '\I, i C l2H5 1,2-dimethyl-s-triazolo[4,3-a]quinolinium iodide (1.6

g., 1 mol.) (from 1-methyl-s-triazolo[4,3-alquinolineand methyl iodide), 2-,8-acetanilidovinylbenzoxazole ethiodide I (2.2 g., '1 mol.), pyridine 10 ml.), and triethylamine (0.5 g., 1 mol.) were refluxed together for one hour. The reaction mixture was cooled and the solid filtered offend washed with acetone. After two'recrystallizav Example 11 .2'-ethyl-3-methylthiazolin0-1 '-s-triazolo- [4,3-a] -quincarbocyanine iodide GHz N 024th orn 2-ethyl-1-methyl-s-triazolo[4,3-a]quinolininm iodide (2.2 g., 1 mol.), 2-,8-anilinovinylthiazoline methiodide (2.26 g., 1 mol.), pyridine ml), triethylamine (1.75 g.,.2 mols.), and acetic anhydride (0.67 g., 1 mol.) were refluxed togetherfor one hour. After cooling, the dye 'was precipitated with ether. The oily' material was washed with ether and then with water. After stirring with acetone, the crystalline dye was filtered ofi, washed with acetone and dried. After two recrystallizations from methyl alcohol, a 24 percent yield of brownish-yellow crystals was obtained, M. P. 253254 C. dec. It

sensitized a gelatino-silver-chlorobromide emulsion to 530 mu with a maximum at 490 mu.

By replacing the l-methyl-s-triazolol3,4-b1benzothiazole of Example 9 by a molecularly equivalent amount of 6-methoxy-1-methyl-s-triazolo[3,4-blbenzothiazole (obtained from 2-hydrazino-6-methoxybenzothiazole and acetic anhydride), 3-ethyl-6'methoxy-2'-methyl-4,S-benzothia-l-s-triazolo[3,4-b]benzothiazolocarbocyanine iodide represented by the following formula:

can be obtained. In like manner, other intermediates selected from those represented by Formula II above can be condensed with intermediates selected from those represented by Formula HI above to give dyes represented by Formula I above. Example 12.6-eth0xy-2'3-diethyloxa-s-triazol0 [3,4-b1- benzothiazolocarbocyanine iodide (lhHu ing, Z-fl-acetanilidiovinylbenzoxazole ethiodide (2.2 g., 1 mol.), ethyl alcohol (10 ml.) and triethylamine (0.5 g., 1 mol.) were added and the mixture refluxed for 15 minutes. After-chilling, the reaction mixture was treated with ether. The solid, which separated, was washed with ether, then with water and finally treated with acetone. After chilling, the dye was filtered'ofi and washed with acetone. After two recrystallizations from ethyl alcohol, an 11% yield of light brown crystals was obtained; M. P. 250-251 C. dec, The dye sensitized a brornoiodide emulsion to 550 mu with maximum sensitivity at 520 mu.

Example I3.7'-chlam-2?,3-diethyloxa-s-triazolo [3,4-b1- benzothiazolocarbocyanine iodide 7-chl0ro-l-methyl-s'triazololl l b] benzothiazole (1.1 g., 1 mol.) and diethyl sulfate (3 g., 1 mol. plus 400% excess) were heated together at -170 C. for 2 hours. After cooling, 2-6-acetanilidovinylbenzoxazole ethiodide (2.2 g., 1 mol.), ethyl alcohol (10 ml.) and triethylamine (3 g., 1 mol. plus 500% excess) were added and the mixture was refluxed for 15 minutes. After chilling, the reaction mixture was treated with ether. The solid, which separated, was'washed with ether, then with water and finally treated with acetone. After chilling, the dye was filtered oil and washed with acetone. After two recrystallizations from ethyl alcohol, a 7% yield of orange crystals was obtained; M. P. 208-210 C. dec. The dye sensitized a bromoiodide emulsion to 560 mu with maximum sensitivity at 520 mu.

Example I4.-7'-chloro-2',3-diethylthia-s-triazolo [3,4-b

benzothiazolocarbocyanine iodide 7-chloro-l-methyl-s-triazolol3,4 blbenzothiazole (1.1 g., 1 mol.) and diethylsulfate (3 g., 1 mol. plus 400% excess) were heated together at l60-l70 C., for 2 hours. After cooling, 2-;3;acetanilidovinylbenzothiazole ethiodide (2.25 g., 1 mol.), ethyl alcohol (10 ml.) and triethylamine (3 g., 1 mol. plus 500% excess) were added and the mixture was refluxed 15 minutes. After chilling, the reaction mixture was treated with ether. The solid, Which separated, was washed with ether, then with water and'finally treated with acetone. After chilling, the dye was filtered off and washed with acetone. After two recrystallizations from ethy-l'alcohol, a 6% yield of dark crystals was obtained; M. P. 230-231 C. dec. The dye sensitized a bromoiodide emulsion to 630 mu with maximum sensitivity at 5 60 mu. 7

As shown above we have found that our new dyes spectrally sensitize photographic silver halide emulsions when incorporated therein. fulior extending the. spectral sensitivity of the customarily employed gelatino-s'ilver-chloride,' gelatino-silverg chlorobromide, gelatino-silver-bromide and gelatino-sil- The dyes are especially usever-bromiodide developing-out emulsions. -To prepare sions are simple and are known to those skilled in the art. In practice, it is convenient to add the dyes to the emulsions in the form of a solution in an appropriate solvent. Methanol or acetone has proved satisfactory as a solvent for most of our new dyes. Where the'dyes are quite insoluble in methyl alcohol, a mixture of methyl alcohol and pyridine is advantageously employed as a solvent. The dyes are advantageously incorporated in the finished, washed emulsions and should be uniformly distributed throughout the emulsions. The particular solvent used will, of course, depend on the solubility properties of the particular dye.

The concentration of the dyes in the emulsions can vary widely, e. g., from 5 to 100 mg. per liter er flowable emulsion. The concentration of the dyes will vary according to the type of emulsion and according to the effect desired. The suitable and most economical concentration for any given emulsion will be apparent to those skilled in the art, upon making the ordinary tests and observations customarily used in the art of emulsion making. To prepare a gelatino-silver-halide emulsion sensitized with one or more of our new dyes, the following procedure is satisfactory.

A quantity of dye is dissolved in methyl alcohol or acetone (or a mixture of methyl alcohol andpyridine) and a volume of this solution, which may be diluted with water, containing from 5 to 100 mg. of dye, is slowly added to about 1000 cc. of gelatino-silver-halide emulsion, with stirring. Stirring is continued until the dye is thoroughly dispersed in the emulsion. v

With mostof our dyes, from to mg. of dye per liter of gelatino-silver-bromide or bromoiodide emulsion (containing about g. or" silver halide) suffices to produce the maximum sensitizing eitect. 'With the finer grain emulsions, somewhat larger concentration of dye may be needed to producethe'maximum sensitizing effect.

The above statements are only illustrative, as it will be apparent that the dyes can be incorporated in photographic emulsions by any of the other methods custom arlly employed in the art, e. g., by bathing a plate or film upon which an emulsion is coated in a solution of the dye in an appropriate solvent. However, ibathing methods are ordinarily not to be preferred. Emulsions sensitized with the dyes can be coated on suitable supports, such as glass, cellulose derivative film,- resin film benzotriazole, nitrohenzimidazole', '5-i1iil0lild3ZGi6, etc.,. (see Moos-5111c Theory of the Photographic, Process.

MacMillan Pub, 1942, pg. 460), or mixtures thereof), hardeners (e. g., formaldehyde (U. SI 1 ,763,533), chronie alum (U. S. 1,763,533), glyoxal '(Ge'r. 538,713) dibromacrolein (Br. 406,750), etc.), color couplers (e. g., such as those described in 'U. S. Patent 2,423,730, Spence and Carroll .U. S. Patent 2,640,776, issued Iune'Z, "1953,'-etc.), or mixtures of such. addenda. Dispensing agents for color couplers, suchas substantially 'water'-insoluble, high boiling crystalloidal materials, such as those-set forth in U. S. Patents 2,322,027 and 2,304,940, can also be employed in the above-described emulsions.

10 Y Dyes embraced by Formula I above which are especially useful in practicing our invention include the following:

wherein R, R X, n and Z each have the values given above, and R represents a hydrogen atom, a halogen atom (e. g., chlorine, bromine, etc.), an alkyl group (.6. g., methyl, ethyl, propyl, etc., especially 'a lower alkyl' group), an aryl group (e. g.,' phenyl, o-, m-, and

wherein R and R each represents an alkyl group, X- representsan acid radical, n represents a positive integer of from 1 to 2, Z represents'the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzothia- Zole series, and 2, represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing from five'to six atoms in the heterocyclic ring.

2, A photographic silver halide emulsion containing a carbocyanine dye selected from those represented by the following general formula:

wherein R and R each represents an alkyl group of the i formula C H wherein m represents a positive integer of from 1.to 4, X represents anacid radical, n represents apositive integer of from 1 to 2, Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the. benzothiazole series, and Z repre sents the non-metallic atoms necessary to complete a heterocyclicnucleus selected from the group consisting of those of the thiazole series, those of the benzothiazole series, those of the naphthothiazole series, those of the oxazole series, those of the benzoxazole series, those of the'naphthoxazole series, those of the 'selenazole series,

2-'quinoline series, those of the -4-quinoline series, those of the l isoquinoline series, those of the benzimidaz ole series, those of the 3,3-dialkylindolenine series, and those of the pyridine series.

3. A photographic silver halide emulsion containing a carbocyanine dye selected from those represented by the following general formula: 1

I z N 1 CCH=CHCH=C N--Rl wherein R and R each represents an alkyl group of the formula C I-I wherein m represents a positive integer of from 1 to 4, X represents an acid radical, Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzothiazole series and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzoxazole series. 7

4. A photographic silver halide emulsion containing the carbocya'nine'dye represented by the following formula:

5. A photographic silver halide emulsion containing a carbocyanine dye selected from those represented by the following general formula:

iF-Ri wherein R andR each represents an alkyl group of the formula lC H wherein m represents a positive integer of from 1 to 4, X represents an acid radical, Z represents the non-metallic atoms necessary to complete a heterocyclic'nucleus of the benzothiazole series and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzothiazole series.

6. A photographic silver halide emulsion containing the carbocyanine dye represented by the following formula:

S\ /N S O CH=OH CH=C a N N Cg I Julia 7. A photographic silver halide emulsion containing a carbocyanine dye selected from those represented by wherein R and R each represents an alkyl group of the formula C Hg wherein m represents a positive integer of from 1 to 4, X represents an acid radical, Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzothiazole series and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzoselenazole series.

- 8. A photographic silver halide emulsion containing the carbocyanine dye represented by the following formula:

9. A photographic silver halide emulsion containing a carbocyanine dye selected from those represented by the following general formula:

S /N v S N i Cg I 121-15 11. A photographic silver halide emulsion containing the carbocyanine dye represented by the following formula:

References Cited in the file of this patent UNITED STATES PATENTS 2,439,210 Heimbach Apr. 6, 1948 2,521,959 Anish Sept. 12, 1950 2,525,015 Beersmans Oct. 10, 1950 2,689,849 Brooker Sept. 21, 1954 OTHER REFERENCES C. A., 16, 3101 (Abstract of Brit. Med. Journal, 19221, 514-5).

C. A. 19, ,530 (Abstract of Proc. Roy. Soc., London 9613, 317-33, 1924).' V 

1. A PHOTOGRAPHIC SILVER HALIDE EMULSION CONTAINING A CARBOCYANINE DYE SELECTED FROM THOSE REPRESENTED BY THE FOLLOWING GENERAL FORMULA: 